Add tag links.

lib/pleroma/web/common_api/common_api.ex

@@ -56,9 +56,9 @@ def post(user, %{"status" => status} = data) do
          mentions <- Formatter.parse_mentions(status),
          inReplyTo <- get_replied_to_activity(data["in_reply_to_status_id"]),
          to <- to_for_user_and_mentions(user, mentions, inReplyTo),
-         content_html <- make_content_html(status, mentions, attachments),
-         context <- make_context(inReplyTo),
          tags <- Formatter.parse_tags(status),
+         content_html <- make_content_html(status, mentions, attachments, tags),
+         context <- make_context(inReplyTo),
          object <- make_note_data(user.ap_id, to, context, content_html, attachments, inReplyTo, tags) do
       res = ActivityPub.create(to, user, context, object)
       User.update_note_count(user)

lib/pleroma/web/common_api/utils.ex

@@ -38,9 +38,9 @@ def to_for_user_and_mentions(user, mentions, inReplyTo) do
     end
   end
 
-  def make_content_html(status, mentions, attachments) do
+  def make_content_html(status, mentions, attachments, tags) do
     status
-    |> format_input(mentions)
+    |> format_input(mentions, tags)
     |> add_attachments(attachments)
   end
 
@@ -57,11 +57,22 @@ def add_attachments(text, attachments) do
     Enum.join([text | attachment_text], "<br>\n")
   end
 
-  def format_input(text, mentions) do
+  def format_input(text, mentions, tags) do
     HtmlSanitizeEx.strip_tags(text)
     |> Formatter.linkify
     |> String.replace("\n", "<br>\n")
     |> add_user_links(mentions)
+    |> add_tag_links(tags)
+  end
+
+  def add_tag_links(text, tags) do
+    tags = tags
+    |> Enum.sort_by(fn ({tag, _}) -> -String.length(tag) end)
+
+    Enum.reduce(tags, text, fn({full, tag}, text) ->
+      url = "#<a href='#{Pleroma.Web.base_url}/tag/#{tag}' rel='tag'>#{tag}</a>"
+      String.replace(text, full, url)
+    end)
   end
 
   def add_user_links(text, mentions) do